When telephone equipment having a telephone handset is utilized in environments subject to shock and vibration, it has been found advantageous to utilize a mechanism that restrains the handset from becoming unintentionally dislodged from a handset cradle. Typical environments that warrant the use of a restraining mechanism in accordance with the present invention include, but are not limited to, those frequently observed on board aircraft, maritime vessels, and high speed trains. In such environments, an unrestrained telephone handset may be unintentionally dislodged, possibly becoming a projectile and causing injury to personnel or damage to the handset or other equipment in close proximity to the handset.
There are many mechanisms described in the patent literature and available on the market that are intended to lock and thereby prevent unauthorized use of telephone equipment. Telephone handset locking mechanisms are intended for unintentional or intentional removal of the handset from the handset cradle, either accidentally, intentionally, or the result of the action of a child or a pet. The present invention is not intended as a telephone lock mechanism but rather as a restraining mechanism for a telephone handset and for one hand removal for use thereof.
Although considerable effort has been directed to developing a telephone handset restraining mechanism, not a locking mechanism, the results to date provide only restraining mechanisms utilizing complicated lever mechanisms requiring trigger operation for release of the telephone handset. These earlier efforts to find an acceptable telephone handset restraining and release mechanism tend to be rather difficult to operate in an emergency environment or when used in a mobile vehicle where the driver of the vehicle must remove the telephone handset at the same time as operating the vehicle.
One known latch mechanism restrains the telephone handset in the handset cradle by means of a latch mechanism built into the yoke portion of the handset. The latch mechanism restrains the handset by engaging the top of an upstanding pin attached to the telephone itself. This pin protrudes outward from the telephone base and is engaged by the latch mechanism when the handset is cradled. A release button is provided on the handset to disengage the latch mechanism from the pin. Unfortunately, this early attempt at telephone handset restraining requires a specially modified telephone set resulting in a costly initial purchase and replacement item.
Another known system for restraining a telephone handset utilizes an ordinary spring as part of a toggle type latch. In environments where vibration is present, designs using ordinary springs must be carefully analyzed or avoided. Every spring/mass system has a natural resident frequency and ordinary springs have little dampening. If an environmental vibration frequency matches the resonant frequency of the spring/mass system, the spring will not perform its desired function. For this reason, use of springs having a low dampening component are not preferred.